Visible-Light-Driven Water Oxidation by a Molecular Manganese Vanadium Oxide Cluster

摘要

Photosynthetic water oxidation in plants occurs at an inorganic calcium manganese oxo cluster, which is known as the oxygen evolving complex (OEC), in photosystem II. Herein, we report a synthetic OEC model based onamolecular manganese vanadium oxide cluster, [Mn4V4O17(OAc)(3)](3-). The compound is based on a [Mn4O4](6+) cubane core, which catalyzes the homogeneous, visible-light-driven oxidation of water to molecular oxygen and is stabilized by a tripodal [V4O13](6-) polyoxovanadate and three acetate ligands. When combined with the photosensitizer [Ru(bpy)(3)](2+) and the oxidant persulfate, visible-light-driven water oxidation with turnover numbers of approximately 1150 and turnover frequencies of about 1.75 s(-1) is observed. Electrochemical, massspectrometric, and spectroscopic studies provide insight into the cluster stability and reactivity. This compound could serve as a model for the molecular structure and reactivity of the OEC and for heterogeneous metal oxide water-oxidation catalysts.